Abstract Cyanobacterial blooms are a potential threat to human communities and ecosystems. Since the late 1980s, researchers have reported harmful cyanobacterial colonies in Patos Lagoon (PL), the largest coastal lagoon in South America. Most studies concerning harmful blooms in PL have focused on its biology and on its southernmost estuarine region, with little information about its displacement inside the lagoon and the influence of physical forces on its dynamics. This study uses satellite-derived information (normalized difference chlorophyll-a index – NDCI), river discharge data, and meteorological data (wind speed and direction, rainfall, and air temperature) to analyze two bloom episodes in PL, during the austral summer of 2019/2020, specifically in its larger, limnic portion. A 30-year meteorological time series was used to contrast the same summer period. Two remote sensing images from Sentinel-2 were taken of PL margins, near their central portion. The summer of 2019/2020 was drier when compared with the historical data, characterizing low river discharge. This environmental condition was coupled with high temperature, which implies thermal stratification in summer even at 2-m depth sites, which might have promoted cyanobacterial growth and accumulation inside PL. Moreover, weak winds (<<6 m s−1) seemed to accumulate cyanobacterial patches on the water surface, including after vertical mixing caused by strong winds (>6 m s−1). The NDCI values represented the two days of blooms, with higher values occurring under higher water temperatures and low wind speeds. ecosystems 1980s s , (PL) America region dynamics satellitederived satellite derived normalized chlorophylla chlorophyll NDCI, NDCI) direction rainfall temperature 20192020 2019 2020 larger portion 30year year 30 period Sentinel2 Sentinel 2 Sentinel- margins 2019/202 2m sites Moreover <<6 6 (<< s−1 s1 1 surface >6 (> s−1. . speeds (PL 2019202 201 202 3 2019/20 << (< s− > ( 201920 20 2019/2 < 20192 2019/

Abstract In freshwater, saxitoxins (STX) are produced by different cyanobacteria genera, including Raphidiopsis. Data regarding cytogenotoxicity effects of STX on human cells are scarse, this merit further studies of its toxicology. This study assessed the cytotoxicity and the chromosome instability of STX on SHSY-5Y human cell line. The CBMN assay allows the detection of chromosome breaks and abnormal chromosomal segregation. Additionally, in silico systems biology approach, used to search for known and predicted interaction networks, was applied to study the interactions between STX and SHSY-5Y cellular components. The results of the CBMN assay demonstrated that STX concentrations of 2.5 – 10 µg/L induced cytostasis and chromosome instability in a dose-response relationship. Apoptosis was detected after exposure of SHSY-5Y cultured cells to STX concentration of 10 µg/L. The results of the systems biology analysis revealed the interaction of STX with proteins related with acetylcoline pathway, cell cycle regulation and apoptosis. Furthermore, combining the in vitro and in silico approachs, it was possible to suggest a mechanism of action of STX in SHSY-5Y cells. Overall, the data demonstrated the cytotoxicity and mutagenicity of environmentally relevant concentrations of STX. These results should be considered when setting up guidelines for monitoring STX in water supply.

Abstract Background Blooms of the saxitoxin-producing cyanobacterium Cylindrospermopsis raciborskii have been contaminating drinking water reservoirs in Brazil for many years. Although acute effects of saxitoxin intoxication are well known, chronic deleterious outcomes caused by repeated saxitoxin exposure still require further investigation. The aim of the present work is to investigate the effects of consumption of drinking water contaminated with C. raciborskii for 30 days on learning and memory processes in rats. Methods The effects of saxitoxin (3 or 9 μg/L STX equivalents) or cyanobacteria on behavior was determined using the open field habituation task, elevated plus maze anxiety model task, inhibitory avoidance task, and referential Morris water maze task. Results No effects of saxitoxin consumption was observed on anxiety and motor exploratory parameters in the elevated plus maze and open field habituation tasks, respectively. However, groups treated with 9 μg/L STX equivalents displayed a decreased memory performance in the inhibitory avoidance and Morris water maze tasks. Conclusions These results suggest an amnesic effect of saxitoxin on aversive and spatial memories.

Background The present work aimed to evaluate the antimycobacterial activity and cytotoxicity of Microcystis aeruginosa toxins, the MC-LR variant and purified extract of [D-Leu1] microcystin-LR. Methods The antimicrobial activity of M. aeruginosa extract and microcystin was evaluated by resazurin microtiter assay against Mycobacterium tuberculosis, M. terrae, M. chelonae and M. kansasii. The cytotoxicity assay was performed by trypan blue exclusion against the HTC cell line. Results Antimicrobial activity was observed in the hexanic extract of M. aeruginosa (RST 9501 strain) against M. tuberculosis, including sensitive and resistant strains with minimal inhibitory concentrations (MIC) between 1.93 μM and 0.06 μM. The high activity of M. aeruginosa hexanic extract could be attributed to the major presence of the toxins MC-LR and [D-Leu1] MC-LR that showed activity at MIC between 53 and 0.42 μM against tested mycobacterial strains. Even at the highest concentration tested, no toxicity of M. aeruginosa extracts was identified against HTC cells. Conclusions These preliminary results suggest that [D-Leu1] MC-LR is a promising candidate for the development of a new antimycobacterial agent.

Background Toxic cyanobacterial blooms are recurrent in Patos Lagoon, in southern Brazil. Among cyanotoxins, [D-Leu1] microcystin-LR is the predominant variant whose natural cycle involves water and sediment compartments. This study aimed to identify and isolate from sediment a bacterial strain capable of growing on [D-Leu1] microcystin-LR. Sediment and water samples were collected at two distinct aquatic spots: close to the Oceanographic Museum (P1), in Rio Grande City, and on São Lourenço Beach (P2), in São Lourenço do Sul City, southern Brazil. Methods [D-Leu1] microcystin-LR was isolated and purified from batch cultures of Microcystis aeruginosastrain RST9501. Samples of water and sediment from Rio Grande and São Lourenço do Sul were collected. Bacteria from the samples were allowed to grow in flasks containing solely [D-Leu1] microcystin-LR. This strain named DMSX was isolated on agar MSM with 8 g L−1 glucose and further purified on a cyanotoxin basis growth. Microcystin concentration was obtained by using the ELISA immunoassay for microcystins whereas bacterial count was performed by epifluorescence microscopy. The genus Pseudomonas was identified by DNA techniques. Results Although several bacterial strains were isolated from the samples, only one, DMXS, was capable of growing on [D-Leu1] microcystin-LR. The phylogenetic analysis of the 16S rRNA gene from DMXS strain classified the organism as Pseudomonas aeruginosa. DMXS strain incubated with [D-Leu1] microcystin-LR lowered the amount of toxin from 1 μg.L−1 to < 0.05 μg.L−1. Besides, an increase in the bacterial count–from 71 × 105 bacteria.mL−1 to 117 × 105 bacteria.mL−1–was observed along the incubation. Conclusions The use of bacteria isolated from sediment for technological applications to remove toxic compounds is viable. Studies have shown that sediment plays an important role as a source of bacteria capable of degrading cyanobacterial toxins. This is the first Brazilian report on a bacterium–of the genus Pseudomonas–that can degrade [D-Leu1] microcystin-LR, the most frequent microcystin variant in Brazilian freshwaters.

Os objetivos deste trabalho foram avaliar o perfil de ácidos graxos e o teor de colesterol em mortadelas elaboradas com diferentes óleos vegetais. Nove tratamentos de mortadela foram elaborados com quatro diferentes óleos vegetais (canola, linhaça, oliva e soja), em dois níveis de substituição (50% e 100%). Os ácidos graxos e o teor de colesterol foram separados e identificados por cromatografia gasosa. Houve predominância dos ácidos graxos oleico, linoleico e palmítico. O teor de ácidos graxos saturados foi menor nos produtos que continham óleos vegetais. A relação PUFA/SFA foi menor no tratamento controle, enquanto que o maior valor foi observado no tratamento com 100% de óleo de linhaça. Os teores de colesterol encontrados foram semelhantes entre todos os tratamentos, sendo superior apenas no tratamento contendo 100% de óleo de soja. Logo, exceto o tratamento com 100% de óleo de soja, todos os outros tratamentos com óleos vegetais apresentaram uma melhor qualidade nutricional quando comparados com o controle.

The aim of this study was to evaluate the fatty acid profile and the cholesterol content of mortadella prepared with different vegetable oils. Nine treatments were made with four different vegetable oils (canola, linseed, olive and soy) using two substitution levels (50% and 100%). The fatty acids and the cholesterol content were separated and identified by gas chromatography. There was a prevalence of the oleic, linoleic and palmitic fatty acids. The saturated fatty acids were lower in the products with vegetable oils. The PUFA/SFA relation was lower in the control treatment while the higher value was observed in the 100% linseed oil treatment. The cholesterol levels found were similar between all the treatments, but a reduction of these levels were observed in the treatments, being superior only in treatment containing 100% of soybean oil. Thus, except the treatment with 100% of soybean oil, all the other treatments with vegetable oils showed a better nutritional quality in relation to the control treatment.

A situação da rêde pública de Assistência Médico-Sanitária é analisada para a área metropolitana da Grande São Paulo, constituída por 37 municípios, com uma população de 8 milhões de habitantes. Existe para a área uma unidade sanitária do tipo Centro ou Sub-Centro de Saúde para cada 101.025 habitantes. Não há uma proporção homogênea entre o tamanho da população e o número de unidades sanitárias, pois existem sub-regiões que apresentam desde 22.000 até 136.142 habitantes por Pôsto de Saúde. O número de postos de assistência materno-infantil é de 232, havendo uma unidade para cada 34.400 habitantes, variando esta proporção por sub-região desde 2.444 até 73.500 habitantes por Pôsto. Há um dispensário de tuberculose para cada 380.048 habitantes. A sub-região Norte, com 67.000 habitantes, não conta com nenhum dispensário de tuberculose. Quanto ao Dispensário de Dermatologia Sanitária a proporção de habitantes por unidade é de 570.071. As sub-regiões Norte e Sudoeste, com 155.000 habitantes, não possuem nenhum dispensário de dermatologia sanitária. Observa-se a inexistência de critérios locacionais para as Unidades Sanitárias, a par do déficit quantitativo e qualitativo do atendimento. Foram apontados, entre os principais objetivos da reforma administrativa da Secretaria de Saúde do Estado, descongestionamento da cúpula, centralização normativa, descentralização executiva e integração em nível local das unidades sanitárias. Observou-se que se encontram integrados, física e funcionalmente, somente 25,6% dos Centros de Saúde, 40% dos Sub-Centros, 42,8% dos Dispensários de Tuberculose e 42,8% dos Dispensários de Dermatologia Sanitária. De acôrdo com estudo realizado pela Secretaria da Saúde, em 1970, somente 4,7% dos atendimentos foi considerado ótimo; 62,7% das unidade sanitárias não possuíam material suficiente e 52,3% não contavam com recursos humanos de acôrdo com a lotação prevista de pessoal. A par dêste quadro carencial, observou-se falta de coordenação entre os podêres públicos responsáveis pelas unidades sanitárias, levando a supercobertura de algumas áreas e o total abandono de outras.

The situation of the Public Health Unit Centers care system is analysed by the "Great São Paulo" Metropolitan Area (Brazil) which contains 37 cities and 8 million inhabitants. There is a health unit center to every 101.025 inhabitants. There is no homogeneous proportion between the size of the population and the number of the health unit centers since there are regions of the Metropolitan area that have from 22.000 inhabitants (to every health center) to 136.142. The number of the Maternal and Child Health centers is 232 with 34400 inhabitants to every unit, and the variation by regions goes from 2444 inhabitants (to every unit) to 73500. There is a Tuberculosis Dispensary to every 380048 inhabitants. The Northern region of the Metropolitan Area with 67000 inhabitants does not have any Tuberculosis Dispensary. The proportion founded to the Leprosy Dispensaries is 570071 inhabitants to every unit. The Northern and Southwest region with 155000 inhabitants do not have any Leprosy Dispensary. There is no rational criteria to the geographical localization of the Health Unit Centers beside this occurs a poor quantitative and qualitative medical attendance. Among the main goals of the Administrative Reform of the Health State Department, São Paulo, Brazil we distinguished: normative centralization, executive descentralization and, in local level, integration of the health unit center. Only 25.6% of the Health Centers are integrated physically and functionally, 40.0% of the Subsidiary Centers, 42.8% of the Tuberculosis Dispensaries and 42.8% of the Leprosy Dispensaries. According to the new terminology 21 Health Centers were classified as being of type I, 10 of type II, 16 of type III, 26 of type IV and 138 of type V. This classification is concerned to the established health care programmes. According to the study carried on by the Health State Department, in 1970, only 4.7% of the attendance was considered excellent, 62.17% and 52.3% respectively of the Health Unit Centers did not have enough material and health manpower. Parallel to this poor situation there is a lack of the coordenation among the state, municipal and private medical care organization, contributing to the concentration on some areas and its total absence on others.

A situação da rêde pública de Assistência Médico-Sanitária é analisada para a área metropolitana da Grande São Paulo, constituída por 37 municípios, com uma população de 8 milhões de habitantes. Existe para a área uma unidade sanitária do tipo Centro ou Sub-Centro de Saúde para cada 101.025 habitantes. Não há uma proporção homogênea entre o tamanho da população e o número de unidades sanitárias, pois existem sub-regiões que apresentam desde 22.000 até 136.142 habitantes por Pôsto de Saúde. O número de postos de assistência materno-infantil é de 232, havendo uma unidade para cada 34.400 habitantes, variando esta proporção por sub-região desde 2.444 até 73.500 habitantes por Pôsto. Há um dispensário de tuberculose para cada 380.048 habitantes. A sub-região Norte, com 67.000 habitantes, não conta com nenhum dispensário de tuberculose. Quanto ao Dispensário de Dermatologia Sanitária a proporção de habitantes por unidade é de 570.071. As sub-regiões Norte e Sudoeste, com 155.000 habitantes, não possuem nenhum dispensário de dermatologia sanitária. Observa-se a inexistência de critérios locacionais para as Unidades Sanitárias, a par do déficit quantitativo e qualitativo do atendimento. Foram apontados, entre os principais objetivos da reforma administrativa da Secretaria de Saúde do Estado, descongestionamento da cúpula, centralização normativa, descentralização executiva e integração em nível local das unidades sanitárias. Observou-se que se encontram integrados, física e funcionalmente, somente 25,6% dos Centros de Saúde, 40% dos Sub-Centros, 42,8% dos Dispensários de Tuberculose e 42,8% dos Dispensários de Dermatologia Sanitária. De acôrdo com estudo realizado pela Secretaria da Saúde, em 1970, somente 4,7% dos atendimentos foi considerado ótimo; 62,7% das unidade sanitárias não possuíam material suficiente e 52,3% não contavam com recursos humanos de acôrdo com a lotação prevista de pessoal. A par dêste quadro carencial, observou-se falta de coordenação entre os podêres públicos responsáveis pelas unidades sanitárias, levando a supercobertura de algumas áreas e o total abandono de outras.

The situation of the Public Health Unit Centers care system is analysed by the "Great São Paulo" Metropolitan Area (Brazil) which contains 37 cities and 8 million inhabitants. There is a health unit center to every 101.025 inhabitants. There is no homogeneous proportion between the size of the population and the number of the health unit centers since there are regions of the Metropolitan area that have from 22.000 inhabitants (to every health center) to 136.142. The number of the Maternal and Child Health centers is 232 with 34400 inhabitants to every unit, and the variation by regions goes from 2444 inhabitants (to every unit) to 73500. There is a Tuberculosis Dispensary to every 380048 inhabitants. The Northern region of the Metropolitan Area with 67000 inhabitants does not have any Tuberculosis Dispensary. The proportion founded to the Leprosy Dispensaries is 570071 inhabitants to every unit. The Northern and Southwest region with 155000 inhabitants do not have any Leprosy Dispensary. There is no rational criteria to the geographical localization of the Health Unit Centers beside this occurs a poor quantitative and qualitative medical attendance. Among the main goals of the Administrative Reform of the Health State Department, São Paulo, Brazil we distinguished: normative centralization, executive descentralization and, in local level, integration of the health unit center. Only 25.6% of the Health Centers are integrated physically and functionally, 40.0% of the Subsidiary Centers, 42.8% of the Tuberculosis Dispensaries and 42.8% of the Leprosy Dispensaries. According to the new terminology 21 Health Centers were classified as being of type I, 10 of type II, 16 of type III, 26 of type IV and 138 of type V. This classification is concerned to the established health care programmes. According to the study carried on by the Health State Department, in 1970, only 4.7% of the attendance was considered excellent, 62.17% and 52.3% respectively of the Health Unit Centers did not have enough material and health manpower. Parallel to this poor situation there is a lack of the coordenation among the state, municipal and private medical care organization, contributing to the concentration on some areas and its total absence on others.

Três triterpenos pentacíclicos inéditos foram isolados da resina de Protium kleinii. Suas estruturas, 3-oxo-11beta,16beta-diidróxi-urs-12-eno (1), 3-oxo-11beta-hidróxi-urs-12-eno (2) e 3-oxo-11beta-hidróxi-olean-12-eno (3), foram elucidadas por espectroscopia de RMN. A administração sistêmica destes compostos (10-100 mg kg-1, i.p.) foi capaz de inibir tanto a primeira quanto a segunda fase da nocicepção induzida pela formalina em camundongos. Em adição, foram isolados os triterpenos conhecidos 3beta,16beta-dihidróxi-urs-12-eno (breina) (4) e uma mistura de alfa (5)- e beta-amirina (6).

Three novel pentacyclic triterpenes have been isolated from the resin of Protium kleinii and their structures elucidated by NMR spectroscopy as 3-oxo-11beta,16beta-dihydroxy-urs-12-ene (1), 3-oxo-11beta-hydroxy-urs-12-ene (2) and 3-oxo-11beta-hydroxy-olean-12-ene (3). The systemic administration of the above compounds (10-100 mg kg-1, i.p.) was able to inhibited both first and second phase of the formalin-induced nociception in mice. The known triterpenes 3beta,16beta-dihydroxy-olean-12-ene (brein) (4) and a mixture of alpha (5)- and beta-amyrin (6) were also found.

This paper describes mortality trends for homicides, suicides, traffic accidents and other external causes in the entire population, adolescents, and youngsters, from 16 countries in the Region of the Americas. This study used the information compiled by the Pan American Health Organization data bank from 1980 until the last year in the 90's in which data was available for each country. A description of different subgroups of adolescents and young people, by age, and sex, is provided. Results indicate that in most countries (Canada, USA, Ecuador, Mexico, Chile, Costa Rica, Trinidad and Tobago, and El Salvador), mortality trends due to external causes have been decreasing in the entire population, as well as among adolescents and young people. Colombia and Brazil are the only countries analyzed which have increasing mortality rates by external causes in their populations. The countries with highest mortality rates due to external causes among adolescents and young people, in decreasing order, are: Colombia, El Salvador, Venezuela, Brazil and Puerto Rico. The primary external causes of death in the entire population, as well as among adolescents and young people, are traffic accidents. However, in almost all of the countries analyzed, death rates are decreasing. Ten of the countries analyzed revealed a progressive increase in homicides in all of the age groups studied (Colombia, Puerto Rico, Trinidad and Tobago, Argentina, Uruguay, Panama, USA, Venezuela, and Brazil). The countries with the highest homicide rates among young men, between 15 and 19 years of age, in decreasing order, are: Colombia, El Salvador, Puerto Rico, Venezuela and Brazil. Young men, between 20 and 24 years of age, were the subgroup with the highest homicide rates. In the United States and Brazil, there is an alarming increase in the homicide rate of boys between 15 and 19 years of age. Suicide is a growing problem among adolescents and young people in Cuba, Canada, USA, Trinidad and Tobago, Argentina, and El Salvador. Increasing mortality rates due to homicide reflect the pressing need for epidemiological surveillance and violence prevention programs directed towards adolescents and young people in the Region of the Americas.

Este trabajo describe la tendencia de la mortalidad por homicidios, suicidios, accidentes de tráfico y otras causas externas, en la población total, adolescente y joven, de 16 países de la Región de las Américas. Se utiliza información del período comprendido entre los años 1980 y para el ultimo año disponible de la decada de 1990, proveniente del Banco de Datos de la Organización Panamericana de la Salud. Se realiza una descripción diferencial de los subgrupos de adolescentes y jóvenes, por edad y sexo. Los resultados demuestran que en la mayor parte de los países (Canadá, EEUU, Ecuador, México, Chile, Costa Rica, Trinidad & Tobago y El Salvador) hay una tendencia decreciente en la mortalidad por causas externas, tanto en la población total como en adolescentes y jóvenes. Colombia y Brasil son los únicos países analizados que presentan tasas de mortalidad por causas externas francamente ascendentes en los grupos estudiados. Los países con mayores tasas de mortalidad por causas externa en adolescentes y jóvenes, en orden decreciente, son: Colombia, El Salvador, Venezuela, Brasil y Puerto Rico. Los accidentes de tráfico son el determinante principal de la mortalidad por causas externas en la población total como en adolescentes y jóvenes, presentando tendencias decrecientes en casi todos los países estudiados. En 10 países se observa un ascenso progresivo de la mortalidad por homicidio en todos los grupos estudiados (Colombia, Puerto Rico, Trinidad & Tobago, Argentina, Uruguay, Panamá, EEUU, Venezuela, Ecuador y Brasil). Los países con mayores tasa de mortalidad por homicidio entre los varones de 15 a 19 años son, en orden decreciente: Colombia, El Salvador, Puerto Rico, Venezuela y Brasil. Los varones de 20 a 24 años presentan las tasas mas altas de homicidio dentro de los grupos estudiados. Hay un aumento alarmante de la tasa de homicidio en el grupo de varones de 15 a 19 años, especialmente en EEUU y Brasil. La mortalidad por suicidio es un problema creciente entre adolescentes y jóvenes de Cuba, Canadá, EEUU, Trinidad & Tobago, Argentina y El Salvador. Las tasas crecientes de mortalidad por homicidio reflejan la necesidad inminente de programas de vigilancia epidemiológica y de prevención de violencia dirigidos a adolescentes y jóvenes de la Región de las Américas.

This paper describes mortality trends for homicides, suicides, traffic accidents and other external causes in the entire population, adolescents, and youngsters, from 16 countries in the Region of the Americas. This study used the information compiled by the Pan American Health Organization data bank from 1980 until the last year in the 90's in which data was available for each country. A description of different subgroups of adolescents and young people, by age, and sex, is provided. Results indicate that in most countries (Canada, USA, Ecuador, Mexico, Chile, Costa Rica, Trinidad and Tobago, and El Salvador), mortality trends due to external causes have been decreasing in the entire population, as well as among adolescents and young people. Colombia and Brazil are the only countries analyzed which have increasing mortality rates by external causes in their populations. The countries with highest mortality rates due to external causes among adolescents and young people, in decreasing order, are: Colombia, El Salvador, Venezuela, Brazil and Puerto Rico. The primary external causes of death in the entire population, as well as among adolescents and young people, are traffic accidents. However, in almost all of the countries analyzed, death rates are decreasing. Ten of the countries analyzed revealed a progressive increase in homicides in all of the age groups studied (Colombia, Puerto Rico, Trinidad and Tobago, Argentina, Uruguay, Panama, USA, Venezuela, and Brazil). The countries with the highest homicide rates among young men, between 15 and 19 years of age, in decreasing order, are: Colombia, El Salvador, Puerto Rico, Venezuela and Brazil. Young men, between 20 and 24 years of age, were the subgroup with the highest homicide rates. In the United States and Brazil, there is an alarming increase in the homicide rate of boys between 15 and 19 years of age. Suicide is a growing problem among adolescents and young people in Cuba, Canada, USA, Trinidad and Tobago, Argentina, and El Salvador. Increasing mortality rates due to homicide reflect the pressing need for epidemiological surveillance and violence prevention programs directed towards adolescents and young people in the Region of the Americas.

Este trabajo describe la tendencia de la mortalidad por homicidios, suicidios, accidentes de tráfico y otras causas externas, en la población total, adolescente y joven, de 16 países de la Región de las Américas. Se utiliza información del período comprendido entre los años 1980 y para el ultimo año disponible de la decada de 1990, proveniente del Banco de Datos de la Organización Panamericana de la Salud. Se realiza una descripción diferencial de los subgrupos de adolescentes y jóvenes, por edad y sexo. Los resultados demuestran que en la mayor parte de los países (Canadá, EEUU, Ecuador, México, Chile, Costa Rica, Trinidad & Tobago y El Salvador) hay una tendencia decreciente en la mortalidad por causas externas, tanto en la población total como en adolescentes y jóvenes. Colombia y Brasil son los únicos países analizados que presentan tasas de mortalidad por causas externas francamente ascendentes en los grupos estudiados. Los países con mayores tasas de mortalidad por causas externa en adolescentes y jóvenes, en orden decreciente, son: Colombia, El Salvador, Venezuela, Brasil y Puerto Rico. Los accidentes de tráfico son el determinante principal de la mortalidad por causas externas en la población total como en adolescentes y jóvenes, presentando tendencias decrecientes en casi todos los países estudiados. En 10 países se observa un ascenso progresivo de la mortalidad por homicidio en todos los grupos estudiados (Colombia, Puerto Rico, Trinidad & Tobago, Argentina, Uruguay, Panamá, EEUU, Venezuela, Ecuador y Brasil). Los países con mayores tasa de mortalidad por homicidio entre los varones de 15 a 19 años son, en orden decreciente: Colombia, El Salvador, Puerto Rico, Venezuela y Brasil. Los varones de 20 a 24 años presentan las tasas mas altas de homicidio dentro de los grupos estudiados. Hay un aumento alarmante de la tasa de homicidio en el grupo de varones de 15 a 19 años, especialmente en EEUU y Brasil. La mortalidad por suicidio es un problema creciente entre adolescentes y jóvenes de Cuba, Canadá, EEUU, Trinidad & Tobago, Argentina y El Salvador. Las tasas crecientes de mortalidad por homicidio reflejan la necesidad inminente de programas de vigilancia epidemiológica y de prevención de violencia dirigidos a adolescentes y jóvenes de la Región de las Américas.